1. Field of the Invention
This invention relates to a dry cleaning method and a dry cleaning apparatus for the method using an organic solvent, such as tetrachloroethylene, for a cleaning fluid.
2. Description of the Related Art
In a general dry cleaning using an organic solvent, such as tetrachloroethylene, for a cleaning fluid, pre-cleaning and main cleaning are acted in each predetermined time by using a solvent mixed with a cleaning agent including an oil-soluble surface-active agent in batch process or to be circulated through a filter.
The solvent used in the pre-cleaning or the main cleaning is recycled by purification through distillation and condensation processes because it is not allowed to dispose the solvent to sewerage and price of the solvent is high.
If the solvent is not distilled completely, remained dirt in the solvent not removed by distillation may stick again to cleaning objects as reverse contamination when the solvent is reused. For preventing the reverse contamination, it is already proposed to control volume of distillation correspondingly to absolute contamination level of the used solvent detected by a sensor. It is shown in Japan Utility Model Application Laid-open S57-160651.